Yesterday, The Wall Street Journal published a piece saying that Apple will begin production of a new iPhone in the second quarter of the year, leading to a possible summer launch. The WSJ also continued rumors that Apple is making a less expensive iPhone, which could be launched as soon as the second half of this year, with a four-inch screen and multi-colored shells.
However, the really juicy bits came up later in a Branch discussion kicked off by the WSJ article, which featured tech-writing heavyweights like MG Siegler and John Gruber. Most them seem to agree that:
It's all still speculation at this point, but if any rumors are worth reading, it's probably from these guys.